47 research outputs found
Acoustic separation of circulating tumor cells
Circulating tumor cells (CTCs) are important targets for cancer biology studies. To further elucidate the role of CTCs in cancer metastasis and prognosis, effective methods for isolating extremely rare tumor cells from peripheral blood must be developed. Acoustic-based methods, which are known to preserve the integrity, functionality, and viability of biological cells using label-free and contact-free sorting, have thus far not been successfully developed to isolate rare CTCs using clinical samples from cancer patients owing to technical constraints, insufficient throughput, and lack of long-term device stability. In this work, we demonstrate the development of an acoustic-based microfluidic device that is capable of high-throughput separation of CTCs from peripheral blood samples obtained from cancer patients. Our method uses tilted-angle standing surface acoustic waves. Parametric numerical simulations were performed to design optimum device geometry, tilt angle, and cell throughput that is more than 20 times higher than previously possible for such devices. We first validated the capability of this device by successfully separating low concentrations (~100 cells/mL) of a variety of cancer cells from cell culture lines from WBCs with a recovery rate better than 83%. We then demonstrated the isolation of CTCs in blood samples obtained from patients with breast cancer. Our acoustic-based separation method thus offers the potential to serve as an invaluable supplemental tool in cancer research, diagnostics, drug efficacy assessment, and therapeutics owing to its excellent biocompatibility, simple design, and label-free automated operation while offering the capability to isolate rare CTCs in a viable state.National Institutes of Health (U.S.) (Grant 1 R01 GM112048-01A1)National Institutes of Health (U.S.) (Grant 1R33EB019785-01)National Science Foundation (U.S.)Penn State Center for Nanoscale Science (Materials Research Science and Engineering Center Grant DMR-0820404)National Institutes of Health (U.S.) (Grant U01HL114476
Real-time Monitoring for the Next Core-Collapse Supernova in JUNO
Core-collapse supernova (CCSN) is one of the most energetic astrophysical
events in the Universe. The early and prompt detection of neutrinos before
(pre-SN) and during the SN burst is a unique opportunity to realize the
multi-messenger observation of the CCSN events. In this work, we describe the
monitoring concept and present the sensitivity of the system to the pre-SN and
SN neutrinos at the Jiangmen Underground Neutrino Observatory (JUNO), which is
a 20 kton liquid scintillator detector under construction in South China. The
real-time monitoring system is designed with both the prompt monitors on the
electronic board and online monitors at the data acquisition stage, in order to
ensure both the alert speed and alert coverage of progenitor stars. By assuming
a false alert rate of 1 per year, this monitoring system can be sensitive to
the pre-SN neutrinos up to the distance of about 1.6 (0.9) kpc and SN neutrinos
up to about 370 (360) kpc for a progenitor mass of 30 for the case
of normal (inverted) mass ordering. The pointing ability of the CCSN is
evaluated by using the accumulated event anisotropy of the inverse beta decay
interactions from pre-SN or SN neutrinos, which, along with the early alert,
can play important roles for the followup multi-messenger observations of the
next Galactic or nearby extragalactic CCSN.Comment: 24 pages, 9 figure
Analytical thermal resistances model for eccentric heat source on rectangular plate with convective cooling at upper and lower surfaces
a b s t r a c t Heat sources on rectangular plate with convective cooling at both upper and lower surfaces are common heat transfer application case in electronic packaging. In this paper, in order to find the analytical solution for this problem, a thermal resistances network model was established based on heat flux flow distribution. The model was used to calculate thermal resistance and predict the mean temperature of the heat source. Simulations by commercial software COMSOL3.5 provided a reference for verification of the model. Data comparisons between simulation and analytical solution show that the network model is accurate to calculate the thermal resistance of the discussion cases and the maximum relative error is 3.47%
Buckling optimization of variable stiffness helicoidal composite laminates based on semi-analytical method
Variable stiffness laminates and helicoidal composites have gained significant attention in recent years. This paper introduces a novel structure called variable stiffness helicoidal composite laminates, which combines these two materials. The fibers in each layer are arranged in curved paths, and all the layers are stacked in a helicoidal pattern. To ensure uniform thickness throughout the laminate, an equidistant placement method is proposed for designing the curvilinear fibers. By establishing the energy equation and fitting the displacements with Legendre polynomials, a semi-analytical method is proposed to determine the critical buckling load. An integrated design framework is developed to obtain the optimal design. The optimized models show more than 10% enhancement in the critical buckling load compared to the quasi-isotropic laminate under uniaxial compression and in-plane shear
Probing Cell Deformability via Acoustically Actuated Bubbles
An acoustically actuated, bubble-based technique is developed to investigate the deformability of cells suspended in microfluidic devices. A microsized bubble is generated by an optothermal effect near the targeted cells, which are suspended in a microfluidic chamber. Subsequently, acoustic actuation is employed to create localized acoustic streaming. In turn, the streaming flow results in hydrodynamic forces that deform the cells in situ. The deformability of the cells is indicative of their mechanical properties.
The method in this study measures mechanical biomarkers from multiple cells in a single experiment, and it can be conveniently integrated with other bioanalysis and drug-screening platforms. Using this technique, the mean deformability of tens of HeLa, HEK, and HUVEC cells is measured to distinguish their mechanical properties. HeLa cells are deformed upon treatment with Cytochalasin. The technique also reveals the deformability of each subpopulation in a mixed, heterogeneous cell sample by the use of both fluorescent markers and mechanical biomarkers. The technique in this study, apart from being relevant to cell biology, will also enable biophysical cellular diagnosis
Acoustic Streaming: Probing Cell Deformability via Acoustically Actuated Bubbles
An acoustically actuated, bubble-based technique is developed to investigate the deformability of cells suspended in microfluidic devices. On page 902, measurements of mechanical biomarkers from multiple cells made by T. J. Huang and co-workers are conducted in a single experiment, and integrated with other bioanalysis and drug-screening platforms. It is expected that this technique could provide insights for cell biology studies and biophysical cellular diagnosis
Thermophoretic Tweezers for Low-Power and Versatile Manipulation of Biological Cells
Optical manipulation
of biological cells and nanoparticles is significantly
important in life sciences, early disease diagnosis, and nanomanufacturing.
However, low-power and versatile all-optical manipulation has remained
elusive. Herein, we have achieved light-directed versatile thermophoretic
manipulation of biological cells at an optical power 100–1000
times lower than that of optical tweezers. By harnessing the permittivity
gradient in the electric double layer of the charged surface of the
cell membrane, we succeed at the low-power trapping of suspended biological
cells within a light-controlled temperature gradient field. Furthermore,
through dynamic control of optothermal potentials using a digital
micromirror device, we have achieved arbitrary spatial arrangements
of cells at a resolution of ∼100 nm and precise rotation of
both single and assemblies of cells. Our thermophoretic tweezers will
find applications in cellular biology, nanomedicine, and tissue engineering
Rheotaxis of Bimetallic Micromotors Driven by Chemical–Acoustic Hybrid Power
Rheotaxis
is a common phenomenon in nature that refers to the directed
movement of micro-organisms as a result of shear flow. The ability
to mimic natural rheotaxis using synthetic micro/nanomotors adds functionality
to enable their applications in biomedicine and chemistry. Here, we
present a hybrid strategy that can achieve both positive and negative
rheotaxis of synthetic bimetallic micromotors by employing a combination
of chemical fuel and acoustic force. An acoustofluidic device is developed
for the integration of the two propulsion mechanisms. Using acoustic
force alone, bimetallic microrods are propelled along the bottom surface
in the center of a fluid channel. The leading end of the microrod
is always the less dense end, as established in earlier experiments.
With chemical fuel (H<sub>2</sub>O<sub>2</sub>) alone, the microrods
orient themselves with their anode end against the flow when shear
flow is present. Numerical simulations confirm that this orientation
results from tilting of the microrods relative to the bottom surface
of the channel, which is caused by catalytically driven electro-osmotic
flow. By combining this catalytic orientation effect with more powerful,
density-dependent acoustic propulsion, both positive and negative
rheotaxis can be achieved. The ability to respond to flow stimuli
and collectively propel synthetic microswimmers in a directed manner
indicates an important step toward practical applications
Thermophoretic Tweezers for Low-Power and Versatile Manipulation of Biological Cells
Optical manipulation
of biological cells and nanoparticles is significantly
important in life sciences, early disease diagnosis, and nanomanufacturing.
However, low-power and versatile all-optical manipulation has remained
elusive. Herein, we have achieved light-directed versatile thermophoretic
manipulation of biological cells at an optical power 100–1000
times lower than that of optical tweezers. By harnessing the permittivity
gradient in the electric double layer of the charged surface of the
cell membrane, we succeed at the low-power trapping of suspended biological
cells within a light-controlled temperature gradient field. Furthermore,
through dynamic control of optothermal potentials using a digital
micromirror device, we have achieved arbitrary spatial arrangements
of cells at a resolution of ∼100 nm and precise rotation of
both single and assemblies of cells. Our thermophoretic tweezers will
find applications in cellular biology, nanomedicine, and tissue engineering